<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *,
        html,
        body {
            margin: 0;
            padding: 0;
        }
        
        a {
            text-decoration: none;
        }
        
        ul,
        li {
            list-style: none;
        }
        
        #title {
            color: red;
        }
        
        .container.title {
            font-size: 30px;
            color: blue;
        }
        
        .titile {
            color: pink;
        }
        
        #title:hover {
            color: blue;
            font-weight: bolder;
        }
    </style>
</head>

<body>
    <div class="container">
        <div>
            <span class="'title">第二层级</span>
        </div>
    </div>
</body>

</html>